I migrated data from Oracle to SQL Server, the rows count in Oracle is around 820m rows, but when SSMA finished the migration "message said 100% successfully migrated" the rows count in SQL Server was around 745m rows.
Is there a limit on the number of rows?
There is no limit on number of rows for SSMA
Please keep in mind that Oracle has read consistency, meaning that the cursor will produce rows as they were in the beginning of select. Maybe, when SSMA started to run there were 745m in Oracle.